US Secretary of Energy Ernest Moniz, who is in India for energy talks after postponing a January visit following a diplomatic standoff, said the two sides had to "pick up the pace of negotiations" on a civilian nuclear deal.

While the issue is an important element in bilateral ties, an agreement has been stuck for months over the issue of liability.

The US maintains that the Indian law, which gives accident victims the right to seek damages from plant suppliers in the event of a mishap, is not in line with the International Convention on Supplementary Compensation for Nuclear Damage.

"This must be resolved for the US as well as Indian companies, if nuclear has to be part of the clean energy future," said Dr Moniz at a joint press conference yesterday with deputy Planning Commission chairman Montek Singh Ahluwalia, who maintained that differences had to be resolved in accordance with the Indian law.

The issue is just one of a handful of differences, including US concerns about India's intellectual property rights to drug patents and its restrictions on importing solar power equipment.

The good relationship between India and the US took a downturn in December over the arrest and strip-search of Indian diplomat Devyani Khobragade, 39, the former Deputy Consul General in New York City.

Although allowed to return to India, US authorities have indicted her on charges of visa fraud and underpaying her Indian maid and the case is pending.

Last week US Assistant Secretary of State for South and Central Asian Affairs, Ms Nisha Biswal, who was in India after postponing her January visit to India, noted the two countries do have differences but, added that "the willingness to talk about them indicates that we are indeed confident, mature partners".

Analysts, however, said bilateral ties have yet to fully recover.

"After a three-month gap, there is an attempt to pick up the pieces and get the relationship back on track... but because of timing with the general elections it doesn't look like it is going to be a full scale restoration," former Indian foreign secretary Lalit Mansingh told The Straits Times.

"There were a lot of issues boiling under the surface."

Last month the US filed a World Trade Organisation case against India saying the government was discriminating against US companies as Indian solar developers were allowed to use only locally made equipment.